Regulation of Different Lights on Energy Acquisitions, Microtuber Formation, and Growth of In Vitro-Grown Solanum tuberosum L.

Limited research has been conducted on the regulation of light quality on heterotrophy in in vitro-grown potato plantlets. Here, we investigated the effect of light quality on photosynthetic and heterotrophic abilities as well as microtuber formation and growth of potato plantlets (Solanum tuberosum L. cv. Shepody). Potato plantlets pre-cultivated under white light for 30 days were then transferred to grow under blue (B), green (G), red (R), yellow (Y), and white (W) lights, and parameters including dry weight, photosynthetic pigment, medium solute consumption, delta C-13 value, root activity, and sucrose transport (SUT) gene expression of these plantlets were measured. The results showed that B, G, and W were conducive to the rapid induction of microtubers, while R, and especially Y, delayed microtuber formation. Higher photosynthetic ability was observed in the W treatment, whereas the opposite effect was seen in the monochromatic light treatments. Microtuber growth was primarily dependent on heterotrophy, and B was conducive to microtuber growth. The delay in microtuber formation was related to the high expression of StSUT4 in the root, and better microtuber growth was associated with higher root activity, more medium solute consumption, and a higher expression level of StSUT1 in the roots.